초록 ▼

최종 목표
◦기후변화 대비 지표수-지하수 연동 지하수변동예측 모델 개발
◦대수층 인공함양 주입 및 함양증진 파일럿 시설 설치 및 모니터링
개발내용 및 결과
◦기후변화에 따른 지표수-지하수 연동 지하수 취약성 평가 모델 개발 : 가뭄 취약지 수문요소 분석, 지하수위 변동 자료 분석, 기후변화 시나리오 수집 및 분석, 기후변화 지표수-지하수 연동 예측 모델 개발
◦인공함양에 따른 지하환경변화 및 클로깅 현상 평가 : 수리지화학/생태(미생물) 활용한 지하환경 평가, 인공함양수 주입에 따른 수질변화 평가, 정호주

최종 목표
◦기후변화 대비 지표수-지하수 연동 지하수변동예측 모델 개발
◦대수층 인공함양 주입 및 함양증진 파일럿 시설 설치 및 모니터링
개발내용 및 결과
◦기후변화에 따른 지표수-지하수 연동 지하수 취약성 평가 모델 개발 : 가뭄 취약지 수문요소 분석, 지하수위 변동 자료 분석, 기후변화 시나리오 수집 및 분석, 기후변화 지표수-지하수 연동 예측 모델 개발
◦인공함양에 따른 지하환경변화 및 클로깅 현상 평가 : 수리지화학/생태(미생물) 활용한 지하환경 평가, 인공함양수 주입에 따른 수질변화 평가, 정호주입식 인공함양 능력평가, 수리지질 및 계절별 변동 특성 평가, 하천수-지하수 혼합반응에 따른 수질 변동 특성 평가, 대수층 산화환원 환경변화에 따른 광물학적 특성 평가, 물리/생물/화학적 대수층 및 관정 클로깅 평가
◦융복합형 인공함양 증진 및 관정주입기술 개발 : 대수층 특성(수리 모델링/물리탐사/수리지질 평가)에 따른 관정주입/회수시스템(CARS) 구축, 자연주입/가압주입 인공함양 시스템 구축 및 효과분석, 연구지역 대수층 및 지표환경 특성에 따른 최적 인공함양시설 운영 모의 기법 개발
기대효과
◦미래의 지하수자원의 안정적 공급과 인공함양 기법을 이용한 지하수 자원의 적극적 확보
◦가뭄 등 물부족의 영향으로 지역별/시기별로 불균등한 수자원을 합리적으로 배분하고 확보할 수 있는 방안 도출
◦국내 대수층의 제반 수리지질, 지하 수질환경 등 다양한 문제점을 해결할 수 있는 복합적인 기술 개발자료로서 활용
적용분야
◦가뭄 및 기후변화에 대비한 국가 수자원 정책 수립의 기초자료
◦안정적인 수자원 확보 : 가뭄에 대한 양적/질적 지하수자원 확보
◦국내실정에 적합한 대수층 인공함양 핵심기술 및 실증기술 확보

Abstract ▼

To quantitatively assess Nakdong River basin's water resources vulnerability to climate changes, hydrologic data were collected, systematically organized, and modeled. The data model for the Nakdong River Basin was implemented as a geodatabase. The VELAS model, a fully distributed hydrologic model,

To quantitatively assess Nakdong River basin's water resources vulnerability to climate changes, hydrologic data were collected, systematically organized, and modeled. The data model for the Nakdong River Basin was implemented as a geodatabase. The VELAS model, a fully distributed hydrologic model, was applied for the period from the year 2001 to 2050. RCP4.5 and RCP8.5 climate scenarios from Korea Meteorological Administration were collected for the development of a model with groundwater-surface water coupling capability. Prospective rainfall and air temperature data in South Korea were downscaled by 1 km or 12.5 km resolutions. And, future land use change was predicted through the analyses of the past land use changes.
Drought can be defined in different ways depending on a scientific or socioeconomic perspective. Accordingly, many sets of drought indices exist, representing different drought nature. Therefore, drought indices should be used with caution, considering the locality, hydrologic properties, climate, and infrastructure of the water supply. Droughts tend to occur every five to six years in Korea. Since 1990, drought damages have been reduced with the development of irrigation techniques and construction of multi-purpose dams.
Multi-criteria decision processes, including a resistivity survey, in-situ test, hydrogeologic survey, and groundwater flow modeling, were performed to secure the groundwater resource for the agricultural use in Sachang-ri, Iwon-myeon, Taean-gun where residents suffered from frequent water shortages. Two wells were excavated at two different locations in the area and groundwater was successfully withdrawn from one of the wells from the bedrock aquifer at the depth of 60 to 70 m below the ground level. This case study suggests that the geological survey is useful in the groundwater exploration by elucidating the relationship between subsurface permeable fractures and the fracture zone on the land surface.
A test site for the development of integrated core technologies in the aquifer recharge system was established and a conceptual system was designed in the area of Daesan-myeon, Changwon City. The various methods including hydrogeophysical surveys and a biogeochemical study were applied to characterize the aquifer properties. The designed system is a kind of ASTR system, and nominated as CARS (Convergent Aquifer Storage, Transfer and Recovery) along the riverside.
The alluvial aquifer in the artificial recharge site can be divided into upper layer (0~10 m deep) and lower layer (>25 m deep) based on hydrogeochemical characteristics. Groundwater are mostly anoxic with DO less than 1 mg/L and anaerobic conditions including denitrification, iron and manganese reduction, but limited sulfate reduction. The upper aquifer was affected by agricultural activities and lower aquifer was affected by diluted seawater intruded along river channel. Temporally, small fluctuations in some hydrochemical parameters were observed in the upper aquifer with weak interactions with river water and nearby agricultural fields. In contrast, the lower aquifer showed little variations indicating isolated hydrogeologic environment.
Groundwater monitoring network of the artificial recharge site has been set and operated using 23 automatic measurement devices for monitoring groundwater level and quality. Cross correlation analyses between rainfall, river stage and groundwater level showed that the maximum correlation coefficients of rainfall-groundwater level and river stage-groundwater level were 0.33 and 0.56 with lag times of 1 day and 2 days, respectively. The measured groundwater temperature ranged from 15.7℃ to 16.6℃ and electric conductivity from 5.6 mS/cm to 5.9 mS/cm. The electric conductivity highly decreased during the injection and pumping activities, and slowly recovered to the initial level. These monitoring results imply the possibility of the dual aquifer system of high saline and fresh groundwater in the study site.
Slug tests were conducted for the observation and injection wells periodically to characterize the aquifer system of the site and investigate the change of well condition through the injection-pumping test and well cleaning. For the observation wells, water level recovery patterns were not much different with time. For the injection well, however, the water recovery was slower than the observation wells and were getting slower with time. After well cleaning and replacement of well screen the water level recovery during the slug test was getting faster than before. The periodic slug test could be a cost-effective tool for assessing the performance of groundwater artificial recharge system.
A long-term pumping test was performed to characterize hydraulic connectivity and aquifer properties by pumping. Highly saline groundwater (approximately 4.5~60 mS/cm) in the lower layer (>25 m deep) exists and the temperature was rapidly increasing below the depth of 18m. Pumping test data were analyzed to determine hydraulic parameters (transmissivity and storativity) using various solutions. It is found that the study site is composed of various aquifer types like confined, leaky confined, unconfined aquifer. Transmissivity of the confined aquifer ranges 390~430 m2/d, leaky confined aquifer ranges 0.6~18.25 m2/d and unconfined aquifer ranges 4.36~361.6 m2/d. Storativity ranges from 1.5~1.99. Electrical conductivity value in observation wells changed about 0.2~5.1 mS/cm and temperature changed 0.03~0.52 ℃ during the pumping tests. As the results of electrical conductivity and temperature logging in observation wells, EC values were decreasing.
Step injection tests were performed to characterize injection capacity of recharge wells. Recharge wells which were physically-clogged by fine particles has redeveloped by air surging. Unforced natural injectivity increased at 107~193% rate, and forced injectivity increased at 153~380% rate comparing to that of before-redevelopment. In case of the forced injection, a total of 117,000 m3 of water can be expected to be injected annually. Tracer tests with uranine estimate groundwater linear velocity to be 4.49 m/d between IW-1 and pumping well, and 2.71 m/d between IW-3 and pumping well. However, recovery rate of the injected tracer was higher in IW-3 (45.2%) than IW-1 (15.7%).
Numerical experiment was carried out in order to estimate the sustainability of CARS system of the study site. Model setup was calibrated based on the measured groundwater level data and used for evaluating the efficiency of CARS. Simulation results show that the mean recovery ratio of injected surface water range from 63 to 84% and the mean residence time of injected water is 43~94 days, which indicated that the CARS system of the study site is fairly efficient. The lower gravel layer shows much better efficiency than upper sand layer for artificial recharge.
A new type of in-situ hydraulic permeameter was developed to determine saturated vertical hydraulic conductivity (VHC) of unsaturated sediments from hydraulic experiments using Darcy’s law. Darcy flux and hydraulic gradient can be measured using the system, and the saturated VHC can be determined from the relationship between them using Darcy’s law. Evaluations in laboratory and in field conditions were performed to see if the proposed permeameter give reliable and valid measures of the saturated VHC. Results from the evaluation tests indicate that the permeameter proposed in this study can be used to measure saturated VHC of unsaturated sediments with high accuracy.
Well logging in groundwater observation wells makes a detailed record of the borehole fluid as well as the hydraulic characteristics of alluvium, and vertical electrical sounding (VES) reveals sedimentary facies of the overall alluvium. A horizontally continuous thick alluvial layer is developed, while the considerable change of natural gamma intensity means different sedimentary environments at the boundary of 12 m. Considering the difference of electrical conductivity in each borehole, the variation of the electrical resistivity and fluid electrical conductivity represents the flow of groundwater in the study area. As the results of two dimensional electrical resistivity monitoring and temperature and electrical conductivity logs, the aquifer are very heterogeneous and shows distinct connectivity toward the river from the pumping well. Using fluid replacement and conductivity logging method, the vertical profiles of major aquifer were identified and its application is an useful method to estimate the individual aquifer in cased boreholes of artificial recharge sites.
For the chemical analysis, 26 groundwater samples were collected and analyzed. Groundwater samples were characterized by Ca(Na)-HCO3(Cl) type and moving to Na-Cl type from February to August indicating the study area was close to estuary of The Nakdong river. To evaluate the mixing ratio of groundwater and stream water, Si contents were used, and the mixing ratio based on Si content was 52.5%.
In a collaborative effort to investigate the impact of river water injection into the aquifer on the subsurface condition and the biogeochemistry, sediments and groundwater have been collected from the site-installed well cluster. The groundwater analyzed on site indicated clues for microbial activities of Fe(III) and sulfate reduction evidenced by Fe(II) and sulfide concentrations, respectively. Those subsurface and groundwater were incubated in laboratory condition anaerobically, and the results assisted microbial activities of Fe(III) and sulfate reduction. From the incubations, changes of bacterial community structures were analyzed over time, which showed coincidence of obvious increase of genus Geobacter and sulfate-reducing bacteria with the propagation of microbial reduction of Fe(III) and sulfate in the microcosm incubations. In comparison with the bacterial community structures of the intact groundwater samples, the changes of microbial community structures become evident.
In addition, to elucidate formation of bioclogging in the wells, in-situ experiment was designed and set up in a water-curtain cultivation site, where stream water migrates into the aquifer due to heavy pumping of groundwater for green house warming in cold season. Looking at the slide glass samples that had been deployed and retrieved at given time points during the whole 3.5 months, bacterial cells and extracellular polymeric substances that microbes generate have been observed to increase with main inorganic materials associated by confocal laser scanning microscopy. The microbial community analysis on the aggregates on the slide glass assists formation of reduced iron minerals as the main constituents of the bioclogging, since species from genus Geobacter was ranked as 2nd among the total of 3,264 species.
3-dimensional numerical code was developed to assess biological clogging, and the reductions of material properties (porosity and hydraulic conductivity) were simulated due to biomass growth. Biomass growth reduces material properties and reduces pumping rate in the river bank filtration. From our simulated results, the pumping rate was reduced due to biomass growth
The effects of environmental conditions, nutrients, and pollutants on the biofilm formation of sands, collected from the possible artificial recharge site were investigated. Six columns were operated at different water quality conditions. During operation periods, hydraulic conductivities of each column at different depth were also measured and compared. At the end of operation periods, biofilm formation on sand of different depth were measured and compared among different columns. ATP analysis was appeared as a proper method for measurement of biofilm formation. During continuous operation, active biofilm formation was observed mostly within 5 cm of soil depth of column, and hydraulic conductivity and biofilm formation were reduced as soil depth increase. In general, influent conditions gave different effects on biofilm formation. Columns with influent containing carbon or nitrogen sources showed high reduction of hydraulic conductivity compared to other conditions. Especially, column with carbon source showed very active biofilm formation, whereas no significant effect was observed with phosphorus source. Effects by influent containing metals were also investigated. In these cases, all metals did not show any reductions of hydraulic conductivity as the soil depth increase. However, slight reductions of ATP, DHA, and biomass contents were observed.
Sand, Activated carbon, Anthracite, and Fiber pellet as the filter media were applied to treat the recharged water through column tests. Water treatment conditions such as the removal rate of the particulate, flow-through rate, and ripening time were determined. The significant variation of water quality was observed mostly within 1 hours after passing original river water through the column of filter media.
Oxidation of dissolved ferrous iron (Fe(II)) by dissolved oxygen was influenced by the geochemical conditions of the artificial groundwater prepared to simulate the groundwater composition at the Changwon demonstration site. For example, under the 2mM bicarbonate condition, major changes in dissolved oxygen, Fe(II), pH, redox potential, and electrical conductivity occurred within 60 min from the start of the reaction, followed by stable values afterwards. About 45 ppm Fe(II) remained after the anoxic artificial groundwater reached equilibrium with dissolved oxygen. Thermodynamic calculations suggested that this concentration was in the range of the equilibrium values with lepidocrocite or goethite under the measured pH condition. Based on the findings of the impact of bicarbonate on the final dissolved Fe(II) concentration in equilibrium with dissolved oxygen, further oxidation experiments are on-going varying bicarbonate concentrations. X-ray diffraction showed that lepidocrocite, amorphous ferric (hydr)oxide, and goethite precipitated depending on the geochemical conditions. The results so far obtained show that pH and precipitation of calcite may play important roles in determining the oxidation products and mechanisms in the oxidation of Fe(II) by dissolved oxygen.

목차 Contents

• 표지 ... 1
• 제 출 문 ... 4
• 최종보고서 요약서 ... 6
• 요 약 문 ... 7
• SUMMARY ... 15
• Contents ... 20
• 목 차 ... 22
• 제 1 장 연구개발과제의 개요 ... 24
• 제 1 절 연구 배경 및 필요성 ... 26
• 제 2 절 연구 목적 ... 29
• 제 3 절 연구 범위 ... 34
• 제 2 장 국내외 기술개발 현황 ... 38
• 제 1 절 선행기술 조사 ... 40
• 제 2 절 선행 연구사업 수행 현황 ... 43
• 제 3 장 연구개발 수행내용 및 결과 ... 46
• 제 1 절 기후변화에 따른 지하수 자원 취약성 평가 ... 48
• 1. 기후변화에 따른 지표수-지하수 연동 수자원 취약성 평가 ... 48
• 2. 가뭄현황 분석 ... 98
• 3. 상시 가뭄지역에서의 지하수탐사 연구 ... 102
• 제 2 절 융복합 인공함양시험시설 운영평가 ... 114
• 1. 지하수위/수질 조사 ... 114
• 2. 순간수위변화 시험 ... 140
• 3. 지하수 관측공 모니터링 ... 143
• 4. 장기 양수시험 ... 146
• 5. 주입가능량 평가 ... 162
• 6. 지하수 유동 모델링 ... 169
• 7. 비포화 다공성 매질의 포화 수리전도도 측정 ... 174
• 8. 물리탐사 및 물리검층을 이용한 시험부지 선정 및 수리지질특성 평가 ... 183
• 제 3 절 인공함양에 따른 지하환경 변화 및 클로깅 평가 ... 214
• 1. 인공함양지 지하수질 조사 ... 214
• 2. 인공함양 연구부지 삼중수소(3H) 분포 ... 221
• 3. 지하수질의 생화학적 평가 ... 224
• 4. 대수층 환경변화에 따른 미생물 변화 ... 228
• 5. 대수층 클로깅 모사를 위한 3차원 수치 모델 개발 ... 237
• 6. 인공함양 시스템에서의 생태환경 영향 평가 ... 246
• 7. 인공함양 주입수 수처리 장치 개발 ... 270
• 8. 여재 컬럼 수처리에 의한 수질변화 ... 277
• 9. 클로깅 유발 삼가철 (수)산화물에 대한 실험 광물학적 연구 ... 288
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 294
• 제 1 절 목표 달성도 ... 296
• 1. 최종 연구목표의 달성도 ... 296
• 2. 3차년도 목표 달성도 ... 297
• 제 2 절 관련 분야에의 기여도 ... 298
• 제 5 장 연구개발결과의 활용계획 ... 300
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 304
• 제 1 절 제41회 국제수리지질학회(IAH) ... 306
• 제 2 절 EGU General Assembly 2014 ... 309
• 제 3 절 제4차 INCC 2014 국제학회 ... 311
• 제 4 절 Goldschmidt 2014 ... 313
• 제 5 절 제14차 SCA 학회 ... 315
• 제 7 장 참고문헌 ... 318
• 끝페이지 ... 327